FN M4A1 Block 1 SOCOM Upper Receiver Group, Military Collector, semi-auto 14.7" carbine - Complete

ships from our shop in 5 to 8 days (+/-), a little longer during peak demand

FN M4A1 Block 1 Military Collector - Complete Upper Receiver

Military replica, made to the same specifications as the military-issue M4A1, however without the select fire feature.

This is a unique and great addition to anyone's military style collection.  And, what a name.  FN !


  • Anodized, flat-top receiver with MIL-STD 1913 rail (12 o'clock)
  • FN 14.7" chrome-lined, button-broached, 1:7-twist barrel with A2-style compensator, welded to 16" with FN military CAGE code
  • M4A1 side sling swivel inside the A-frame "F" height front sight base
  • Mil-spec M4 RAS Adapter rail with covers (Knights Armament, a military contractor) - 3 large for top and each side and 1 small for bottom
  • Mil Spec rear BUIS from Matech / Picatinny Engineering branded
  • FN milspec BCG with MPI/HP
  • FN milspec charging handled
  • No forward vertical grip included

The FN 15 rifle series is based on FN's semi-automatic, direct impingement platform for the 5.56x45mm, .223 Remington, and .300 AAC Blackout (7.62x35mm) cartridges, and offers something for everyone, whether the application is tactical, collector, or target/competition.

This is what we call a "take-off," and is factory new.  We take a complete Factory FN Military Collector rifle and separate the upper from the lower.

Note:  The barrel is 14.7", which is manufacturer specifically for this upper.  The 14.7" barrel allows FN to pin and weld a standard A2 "birdcage" front sight.  The 14.5" barrels require an extended flash hider to get to 16+ inches.  Every time a flash hider is pinned and welded, something suffers.  With Colt, they use an ungodly amount of silver solder, and you get a big weld spot.  When Potomac Armory does our pin and welds for Charlie's custom builds, we get a much more modest weld, but it is still there.  FN welds on the side, and then uses a gray paint of sorts to try to cover up the weld.  We have had customers complain that the gray paint is ugly.  You cannot win.  When you pin and weld, something has to give.  The gray paint does not quite match the color of the A2 phosphating. 

With respect to the look of the pin and weld, we will not accept returns for defect due to color.  You can return, subject to restocking and shipping fees, but not for cosmetics of your weld.  If you don't like it, you can remove the gray paint with acetone.  We do with a Q-Tip.  Then, you get the weld.  Mostly, don't worry so much about it.  Once you fire 100 rounds, the paint and the phosphating is going to turn color, and you will begin to see some green which is from the copper jacketed bullets.  This is a war machine, not a museum piece.

Charlie's offers FN and Colt SOCOM uppers. for Colt see these options:  Colt M4 SOCOM Upper  , Colt M4 SOCOM factory Upper and free floating M4A1 upper receiver


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